Selective grazing of Lolium perenne and Plantago lanceolata by growing European wild boar (Sus scrofa L.) in a semi-extensive system

In Chile, European wild boar are most commonly produced in a semi-extensive system with access to pastures for grazing. These pastures normally have a very heterogeneous botanical composition. The objective of the study was to determine whether grazing European wild boar select between the grass species L. perenne and the broadleaf species P. lanceolata. Four transects were marked in each of three areas of a pasture containing predominantly L. perenne cv. Arrow AR1 and P. lanceolata cv. Tonic. A total of 15 tillers from L. perenne and 15 P. lanceolata plants were marked along each transect. Male pure-bred European wild boar (n = 18) with nose-rings and an average bodyweight of 11.2 ± 0.25 kg (mean ± SEM) grazed the areas during the evaluation days. For the marked tiller or plant, each leaf length was measured and the dry matter content estimated pre- and post-grazing, with a difference between the measurements pre- and post-grazing demonstrating that grazing had occurred for that leaf. Each transect was evaluated daily for a total of three days. The study was carried out in Summer and repeated in Autumn. The probability of being grazed was significantly greater for the marked P. lanceolata plants than for the L. perenne tillers in both Summer and Autumn (P < 0.01). The quantity of dry matter consumed from each grazed plant was also notably greater for P. lanceolata plants than for the L. perenne tillers in both Summer (P < 0.01) and Autumn (P < 0.0001). A strong positive relationship was found between leaf length and its probability of being grazed. These results show that wild boar do actively select the species of plant to be grazed, with a marked preference for P. lanceolata over L. perenne.